This disclosure relates generally to turbines, and, more specifically, to systems and methods for stress relief in dovetails for axial-mounted turbine rotor blades.
Blades (also sometimes referred to as “buckets”) for gas turbine engines, particularly blades that are coupled to engine hubs using axial dovetails, are subjected to substantial stresses caused by radially-outwardly directed forces imposed on the blades by the rotation of the turbine rotor. Specifically, axial dovetails include one or more axially-extending tangs that are subjected to substantial, unevenly-applied radial loading during turbine operation. Accordingly, loads imposed on axial dovetails, and stresses resulting from the loads, are concentrated in specific areas along the lengths of the tangs due to a non-uniform load path defined by the loads. As such, a useful service life (also referred to as a “low cycle fatigue life”) of a blade, as a whole, is influenced by the useful service life of the dovetails, specifically in areas of load concentration along fillets between dovetail tangs. An increase in service life of a turbine component yields lower costs, as that facilitates replacement of the turbine component at greater time intervals.
Accordingly, it is desirable to provide an axial dovetail construction that facilitates a reduction in loading in areas of load concentration.